Refer to the figure.
The fruit fly Drosophila neotestacea carries a bacterial symbiont; the fly can also be infected by a nematode worm. The figure shows the number of eggs produced by female flies that are or are not infected by the nematode and that have or do not have the bacterial symbiont.
- Assuming that the nematode benefits by being inside the fly, the fly?nematode relationship, when there is no bacterial symbiont, is best described as a(n)